In the related art, when one image is displayed on a large screen, there is a multi-display function in which one image is divided, and is displayed on a plurality of displays. The multi-display function can be executed in an information terminal device in which, for example, Windows (registered trade mark) operating system is installed. Specifically, Windows (registered trade mark) displays divided images that are the divided single target image to be displayed, on the respective display units of a plurality of connected information terminal devices.
However, such a multi-display function of Windows (registered trade mark) could only be performed between Windows and an information terminal device.